Diels-Reese reaction

What is Diels-Reese reaction?

Diels and Reese first reported the conjugate addition between hydroazobenzene and dimethyl acetylene-dicarboxylate in 1934, known as Diels-Reese reaction. The adduct resulting from this reaction can yield three distinct heterocyclic compounds based on the experimental conditions employed.

Diels-Reese reaction - general reaction scheme
Diels-Reese reaction

For instance, the adduct can be converted into 1,2-diphenyl-3-carbomethoxy-5-pyrazolone in acetic acid, dimethyl indole-2,3-dicarboxylate in xylene, or 2-hydroxy-3-anilino-4-carbomethoxy-quinoline in pyridine. The latter can be further transformed into 2,3-dihydroquinoline by decarboxylation and hydrolysis. Moreover, heating the 1:1 adduct in picoline has been explored as an alternative method for this reaction.

Pyrazolones, indoles, and quinolines can be synthesized using this reaction.

References

Diels, O. and Reese, J. (1934), Synthesen in der hydroaromatischen Reihe. XX. Über die Anlagerung von Acetylen-dicarbonsäureester an Hydrazobenzol. [Syntheses in the hydroaromatic series. XX. on the addition of acetylenic dicarboxylic esters to hydrazobenzene.] Justus Liebigs Ann. Chem., 511: 168-182. https://doi.org/10.1002/jlac.19345110114

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